Heat exchanger for a motor vehicle

ABSTRACT

The invention relates to a heat exchanger (100) for a motor vehicle, comprising a first circuit (110) comprising at least one first group of chambers (75) and one second group of chambers (76) intended to be traversed by a heat transfer fluid, and a second circuit (120) intended to be traversed by a coolant, the heat exchanger (100) being configured to implement an exchange of heat between the heat transfer fluid and the coolant, the heat exchanger (100) comprising at least one component (155) for differentiating the flow of heat transfer fluid circulating in the first group of chambers (75) from the flow of heat transfer fluid circulating in the second group of chambers (76) of the first circuit (110).

The present invention relates to the field of heat exchangers for motorvehicles. It applies for preference, although not exclusively, to theheat exchangers used in the air conditioning circuits of such vehicles.

The present invention more particularly relates to heat exchangers whichcomprise a first circuit configured to carry a heat-transport liquid anda second circuit configured to carry a refrigerant fluid. Morespecifically, the present invention relates to such exchangers in whichthe second circuit comprises at least two successive passes ofrefrigerant fluid, and in which the first circuit comprises a pluralityof chambers split into several groups of chambers. The heat exchanger isthen configured to perform an exchange of heat between theheat-transport liquid circulating in at least one of the groups ofchambers and the refrigerant fluid circulating in at least one of thepasses of the second circuit. What is meant here by a “pass” is distinctregions of the second circuit of the heat exchanger which are configuredso that the refrigerant fluid circulates successively within them.According to one particular arrangement, the passes of the secondcircuit may be arranged in such a way that the refrigerant fluidcirculates in parallel between them.

In such exchangers, also known as water-cooled condensers, therefrigerant fluid is admitted to a first pass of the second circuit ingaseous form and then, circulating successively through the variouspasses of the second circuit, in contact with the various groups ofchambers of the first circuit through which chambers the heat-transportliquid circulates, it is progressively condensed until it leaves theexchanger in liquid form.

The technical problem to which the present invention aims to propose asolution is that of the efficiency of the exchange of heat in thevarious passes of the second circuit, notably in those regions of theheat exchanger in which the physical-chemical conversion that is thecondensing of the refrigerant fluid takes place.

In order to increase the efficiency of such a heat exchange, a firstsubject of the present invention is a heat exchanger for a motorvehicle, comprising:

-   -   a first circuit through which a heat-transport liquid is        intended to pass and which comprises a first inlet header via        which the heat-transport liquid is admitted to the first circuit        and a first outlet header via which the heat-transport liquid        leaves the first circuit, the first circuit comprising a        plurality of chambers which are fluidically connected to the        first inlet header and to the first outlet header and are split        into at least a first group of chambers and a second group of        chambers,    -   a second circuit through which a refrigerant fluid is intended        to pass and which comprises a second inlet header via which the        refrigerant fluid is admitted into the heat exchanger and a        second outlet header via which the refrigerant fluid leaves the        heat exchanger, the second circuit comprising at least two        successive passes, the heat exchanger being configured to        perform an exchange of heat between the        heat-transport liquid circulating in at least one of the groups        of chambers and at least one of the passes of the second        circuit,        characterized in that the heat exchanger comprises at least one        differentiation member for differentiating the flowrate of        heat-transport liquid circulating per chamber in the first group        of chambers from the flowrate of heat-transport liquid        circulating per chamber in the second group of chambers of the        first circuit.

The presence of the aforesaid differentiation member results indifferent flow velocities for the heat-transport liquid between thegroups of chambers concerned. This has the effect of differentiating theduration of the exchange of heat performed between the heat-transportliquid circulating in these groups of chambers and the refrigerant fluidcirculating in the corresponding passes of the second circuit. Theinvention thus achieves its stated objective by notably making itpossible to increase a duration of the exchange of heat between theheat-transport liquid circulating in one group of chambers in which theflowrate of this heat-transport liquid is lowest and the refrigerantfluid circulating in a pass of the second circuit in contact with thisgroup of chambers.

According to one particularly advantageous embodiment, each chamber isdelimited by at least two plates, each plate comprising a bottom wallsurrounded by a turned-up edge, the bottom wall being provided with atleast one opening which at least in part delimits the first inletheader, the two plates being positioned one inside the other.Advantageously, the bottom walls of the plates delimiting the chambersof the first circuit have a substantially planar overall shape.

The heat exchanger according to the invention is therefore made up of astack of plates as previously described stacked in a direction ofstacking substantially perpendicular to an overall main plane ofextension of the bottom wall of each of these plates. This has theeffect that the aforementioned first inlet header is formed of the stackof the aforesaid openings pierced in the bottom walls of the platesdelimiting the chambers of the first circuit.

The first inlet header for admitting the heat-transport liquid into thefirst circuit of the exchanger according to the invention thereforesubstantially assumes the form of a conduit extending through the heatexchanger according to the invention. According to a preferred althoughnot exclusive embodiment, the openings formed in the bottom walls of theplates that make up the heat exchanger according to the invention arearranged in such a way that the aforesaid first inlet header extendssubstantially perpendicular to the bottom walls of the plates whichdelimit the chambers of the first circuit and, therefore, substantiallyparallel to the direction of stacking of the aforesaid plates.

According to a first example of how the invention may be embodied, thefirst inlet header comprises a first conduit supplying the first groupof chambers and a second conduit supplying the second group of chambers,the differentiation member involving a second bore section of the secondconduit that is smaller than a first bore section of the first conduit.What is meant here by a bore section is the surface area of a crosssection of the conduit concerned, measured in a plane substantiallyperpendicular to the main direction of extension thereof. The foregoingtherefore means that the flowrate of heat-transport liquid circulatingin the second conduit of the first inlet header is smaller than theflowrate of heat-transport liquid circulating in the first conduit ofthe first inlet header.

Advantageously, according to such an example, a ratio between the secondbore section of the second conduit and the first bore section of thefirst conduit is comprised between 0.4 and 0.8.

More specifically, according to a first embodiment of this first exampleof how the invention may be embodied, the bottom walls of the at leasttwo plates each comprise at least a first opening and a second opening,respectively constituting the first conduit and the second conduit ofthe first inlet header.

According to one example of how the invention may be embodied, thesecond bore section is defined by at least one of the second openingsformed in the plate.

To complement this, the aforementioned first bore section and theaforementioned second bore section are respectively defined by thedimensions of at least one of the openings formed in the aforesaid plateor plates. For example, the first bore section is defined by theaforementioned first opening, and the second bore section is defined bythe second opening defined hereinabove.

According to the invention, the differentiation member is formed by atleast a second opening that forms part of the second conduit.

Alternatively, the differentiation member comprises all of the secondopenings of the second conduit.

The above-defined differentiation member that differentiates theflowrate of heat-transport liquid is therefore embodied here by thedifference in bore section between the first opening and the secondopening. In other words again, the differentiation member corresponds tothe second bore section of at least one of the second openings beingsmaller than the first bore section of one of the first openings.

It must therefore be understood here that, in this example of how theheat exchanger according to the invention may be embodied, thedifferentiation of the flowrate of heat-transport liquid between thefirst conduit and the second conduit of the first inlet header is theresult of the geometry of the plates that forms the first circuit and ofthe dimensions of the openings made in the bottom walls of these plates.

According to one example, all of the second openings that define thesecond conduit of the first inlet header may have the same bore section,substantially equal to the aforementioned second bore section. Thedifferentiation member that differentiates the flowrate ofheat-transport liquid is then defined by all of the second openings thatdefine the second conduit. In a variant, just one of the second openingsthat contributes to defining the second conduit has a bore sectionsubstantially equal to the aforementioned second bore section.

In another example, the heat exchanger comprises at least oneheat-transport-liquid supply unit, the supply unit being fluidicallyconnected to the first inlet header which comprises a first conduitsupplying the first group of chambers and a second conduit supplying thesecond group of chambers. The first conduit and the second conduittherefore together form the above-defined first inlet header.Advantageously, in such an example, the bore sections of the firstconduit and of the second conduit are substantially equal.

In this example, the invention anticipates for the supply unit tocomprise a first duct supplying the first conduit and a second ductsupplying the second conduit of the first inlet header, thedifferentiation member involving a second bore section of the secondduct that is smaller than a first bore section of the first duct.Advantageously, a ratio between the second bore section of the secondduct and the first bore section of the first duct is comprised between0.4 and 0.8.

According to another example, the first heat-transport liquid circuitcomprises a third group of chambers which are fluidically connected tothe first conduit of the first inlet header and to the first outletheader successively to the first group of chambers, the heat-transportliquid flowrate differentiation member comprising at least a third boresection of the first conduit, positioned between the first group ofchambers and the third group of chambers, the third bore section beingsmaller than the first bore section of the first conduit.Advantageously, a ratio between the third bore section of the firstconduit and the first bore section of the first conduit is substantiallycomprised between 0.4 and 0.8.

In other words, according to this example, the bore section of the firstconduit according to the invention is reduced in the third group ofchambers of the first circuit. This makes it possible to increase stillfurther the residence time of the heat-transport liquid in the thirdgroup of chambers of the first circuit and, therefore, the duration andefficiency of the exchange of heat between the refrigerant fluidcirculating in the second circuit and the heat-transport liquidcirculating in the third group of chambers.

According to one advantageous example, at least one of the firstopenings that make up the first conduit exhibits the third bore section.

The invention thus makes it possible, through simple means such as thecreation of openings of different dimensions in plates delimiting thechambers of the first circuit of a heat exchanger as has just beendescribed, to modify the flowrate of heat-transport liquid within suchan exchanger, for an increased residence time in contact with therefrigerant fluid and, therefore, for better heat-exchange efficiency.The invention thus achieves its stated objective.

A second aspect of the invention also relates to a thermal conditioningsystem for a motor vehicle comprising at least one heat exchangeraccording to any one of the preceding features. Advantageously, in sucha thermal conditioning system, the heat-transport liquid is glycolwater.

Further features, details and advantages of the invention will becomemore clearly apparent from reading the description, which is providedbelow by way of illustration and with reference to drawings in which:

FIG. 1 is a schematic perspective overview of one example of a thermalconditioning system according to the invention;

FIG. 2 is a schematic view in section on a vertical and transverse planeof the heat exchanger of FIG. 1 showing a first example of how theinvention may be embodied;

FIG. 3 is a schematic view in section on a vertical and transverse planeof the heat exchanger of FIG. 1 showing a second example of how theinvention may be embodied;

FIG. 4 is a schematic view in section on a vertical and transverse planeof the heat exchanger of FIG. 1 showing a third example of how theinvention may be embodied.

It should first of all be noted that although the figures set out theinvention in detail for implementing the invention, these figures may ofcourse be used in order to better define the invention if necessary. Itshould also be noted that these figures set out only a number ofexamples of ways in which the invention may be embodied.

FIG. 1 is a schematic perspective illustration of a thermal conditioningsystem 500 according to the invention.

Such a thermal conditioning system 500 notably comprises a heatexchanger 100 configured to be the site of an exchange of heat between aheat-transport liquid and a refrigerant fluid both circulating withinit. According to one example, the heat-transport liquid is a glycolwater. The heat-transport liquid and the refrigerant fluid are notdepicted in the figures.

Advantageously, the heat exchanger 100 comprises a first circuit 110through which the heat-transport liquid is conveyed, and a secondcircuit 120 through which the refrigerant fluid is conveyed, the firstcircuit 110 and the second circuit 120 being, inside the heat exchanger100, in contact with one another in such a way that an exchange of heatbetween the heat-transport liquid and the refrigerant fluid can occur.

The first circuit 110 of the heat exchanger 100 extends between a firstinlet header 1 via which the heat-transport liquid is admitted to thefirst circuit 110 of the heat exchanger 100 and a first outlet header 2via which the heat-transport liquid leaves the first circuit 110 of theheat exchanger 100.

The second circuit 120 of the heat exchanger 100 extends between asecond inlet header 3 via which the refrigerant fluid is admitted to thesecond circuit 120 of the heat exchanger 100 and a second outlet header4 via which the refrigerant fluid leaves the second circuit 120 of theheat exchanger 100.

According to the example more particularly illustrated in FIG. 1 , theheat exchanger 100 comprises a supply unit 5 via which theheat-transport liquid enters the above-defined first inlet header 1. Thesupply unit 5 is therefore fluidically connected to the first inletheader 1. According to this example, the heat exchanger 100 alsocomprises an outlet unit 50 fluidically connected to the first outletheader 2 and via which the heat-transport liquid leaves the heatexchanger 100.

The refrigerant fluid, admitted to the heat exchanger 100 in essentiallygaseous form, is progressively condensed as it passes through the heatexchanger 100 through an exchange of heat with the heat-transportliquid, until it leaves the heat exchanger 100 in essentially liquidform. In one particularly advantageous configuration, the refrigerantfluid in liquid form is received and stored in a condensation bottle 200arranged near the heat exchanger 100. Advantageously, and to increasethe efficiency of the exchange of heat between the heat-transport liquidand the refrigerant fluid, the latter makes a plurality of passesthrough the second circuit 120, successively in contact with differentregions of the first circuit 110. The various distinct regions of thesecond circuit 120, through which regions the refrigerant fluidsuccessively circulates will, in what follows, be referred to by theterm “passes” of the second circuit 120 of the heat exchanger 100.

FIG. 2 schematically illustrates, in section on a vertical andtransverse plane A visible in FIG. 1 , a heat exchanger 100 according toa first example of how the invention may be embodied.

FIG. 2 again shows the above-defined first inlet header 1, configured toadmit the heat-transport liquid into the first circuit 110 of the heatexchanger 100. This FIG. 2 also again shows the supply unit 5 aspreviously defined, configured to allow the heat-transport liquid toenter the first circuit 110.

With reference to FIG. 2 , the heat exchanger 100 is formed of a stackof N plates 6 a, . . . 6 i, 6 j, . . . 6 n, stacked in a direction ofstacking E arbitrarily referred to in what follows as the verticaldirection V of the heat exchanger 100 and indicated by the axis V inFIG. 2 . It should be noted that the vertical direction V of the heatexchanger 100 can be anything with reference to a vertical direction ofa motor vehicle in which a thermal conditioning system as previouslydescribed and comprising the heat exchanger 100 is placed.

As shown in FIG. 2 , each plate 6 a, . . . , 6 i, 6 j, . . . 6 n, of theheat exchanger 100 is formed of a bottom wall 60 a, . . . , 60 i, 60 j,. . . 60 n the overall shape of which is substantially planar,surrounded by a turned-up edge 61 a, . . . 61 i, 61 j, . . . 61 n, ofwhich the dimensions, measured perpendicular to the main plane ofextension of the bottom wall 60 a, . . . , 60 i, 60 j, . . . , 60 n, aresmall relative to the dimensions of this wall. Only two plates 6 i, 6 j,their bottom walls 60 i, 60 j, and their turned-up edges 61 i, 61 j,have been identified in FIG. 2 . According to the example illustrated inFIG. 2 , the bottom walls 60 a, . . . , 60 i, 60 j, . . . 60 n aresubstantially perpendicular to the above-defined vertical direction V ofthe heat exchanger 100, and are substantially parallel to a plane Pdefined by a longitudinal direction L and a transverse direction T,which are respectively arbitrarily referred to as the longitudinaldirection and as the transverse direction of the heat exchanger 100.

In the heat exchanger 100 according to the invention, the plates 6 a, .. . , 6 i, 6 j, . . . 6 n pairwise delimit chambers 7 a, . . . 7 i, 7 j,. . . , 7 n of the first circuit 110 of the heat exchanger 100, which isto say chambers configured to convey the heat-transport liquid withinthe heat exchanger 100. Only one chamber 7 i, delimited by the plates 6i, 6 j, is depicted in FIG. 2 . The spaces defined between the chambers7 a, . . . , 7 i, 7 j, . . . , 7 n together partially form the secondcircuit of the heat exchanger 100, in which circuit the refrigerantfluid circulates in contact with the chambers 7 a, . . . , 7 i, 7 j, . .. , 71 n of the first circuit 110. It must be appreciated here that thebottom walls 60 a, . . . , 60 i, 60 j, . . . , 60 n, of substantiallyplanar overall shape, have reliefs so that when the corresponding plates6 a, . . . , 6 i, 6 j, . . . , 6 n are stacked in the aforementionedvertical direction V, these walls between them form different volumesrespectively corresponding at least in part to the second circuit 120 ofthe heat exchanger 100 or to chambers 7 a, . . . , 7 i, 7 j, . . . , 7 nof the first circuit 110.

Advantageously, each bottom wall 60 a, . . . , 60 i, 60 j, . . . , 60 ncomprises at least one opening 62 a, . . . , 62 i, 62 j, . . . , 62 nwhich at least partly delimits the first inlet header 1. The first inletheader 1 of the first circuit 110 thus extends substantially over theentirety of the dimension of the heat exchanger 100 in the above-definedvertical direction V thereof, and is formed of the stack of theaforesaid openings 62 a, . . . , 62 i, 62 j, . . . , 62 n.

Advantageously, the chambers 7 a, . . . , 7 i, 7 j, . . . , 7 n of thefirst circuit 110 are organized into mutually independent groups ofchambers, through which groups the heat-transport liquid circulatessuccessively. For example, the chambers 7 a, . . . , 7 i, 7 j, . . . , 7n of the first circuit 110 are organized into a first group of chambers75 and a second group of chambers 76, each group of chambers 75, 76being, within the heat exchanger 100, in contact with a pass, as definedhereinabove, of the second circuit 120 of the heat exchanger 100. Inother words, the first group of chambers 75 is in contact with a firstpass, not depicted, of the second circuit 120, and the second group ofchambers 76 is in contact with a second pass, not depicted, of thesecond circuit 120 and distinct from the first pass. The first group ofchambers 75 and the second group of chambers 76 are indicatedschematically in FIG. 2 .

According to the first example of how the invention may be embodied,which is illustrated in FIG. 2 , the inlet header 1 comprises a firstconduit 10 and a second conduit 11.

As shown by FIG. 2 , the first conduit 10 extends substantially over theentirety of the dimension of the heat exchanger 100 in the above-definedvertical direction V thereof. According to the invention, the secondconduit 11 extends substantially over half of the dimension of the heatexchanger 100 in the vertical direction V thereof. Moreover, as shown inFIG. 2 , the first conduit 10 is formed of the stack, in the verticaldirection V of the heat exchanger 100, of first openings 63 a, . . . ,63 i, 63 j, . . . , 63 n, arranged in the plates 6 a, . . . , 6 i, 6 j,. . . , 6 n, of the heat exchanger 100, and the second conduit 11 isformed of the stack, in the vertical direction V of the heat exchanger100, of second openings 64 a, . . . , 64 i, 64 j, . . . , 64 n, arrangedin the plates 6 a, . . . , 6 i, 6 j, . . . , 6 n, of the heat exchanger100.

In other words, according to the example illustrated in FIG. 2 , thebottom wall 60 a, . . . , 60 i, 60 j, . . . , 60 n, of each plate 6 a, .. . , 6 i, 6 j, . . . , 6 n, that makes up the heat exchanger 100, ispierced with at least a first opening 63 a, . . . , 63 i, 63 j, . . . ,63 n and with at least a second opening 64 a, . . . , 64 i, 64 j, . . ., 64 n, which openings together respectively define the first conduit 10and the second conduit 11 of the first inlet header 1.

According to the invention, the first conduit 10 of the first inletheader 1 is configured to supply heat-transport liquid to theabove-defined first group of chambers 75, and the second conduit 11 ofthe first inlet header 1 is configured to supply heat-transport liquidto the above-defined second group of chambers 76.

Moreover, the invention plans for a first bore section 150 of the firstconduit 10 to be greater than the second bore section 160 of the secondconduit 11, the bore section being defined here in a plane substantiallyperpendicular to the main direction of extension of the conduitconcerned. More specifically, the invention plans for a ratio betweenthe second bore section 160 and the first bore section 150 to becomprised between 0.4 and 0.8.

It should be noted that, according to the first example of how theinvention may be embodied, illustrated more particularly in FIG. 2 , thesupply unit 5 comprises, on the one hand, a first duct 50 fluidicallyconnected to the first conduit 10 of the first inlet header 1 and, onthe other hand, a second duct 51 fluidically connected to the secondconduit 11 of the first inlet header 1.

According to the example more particularly illustrated in FIG. 2 , thefirst conduit 10 and the second conduit 11 each have a substantiallycylindrical shape, with the axis of elongation substantially parallel tothe above-defined vertical direction V of the heat exchanger 100.According to such an example, the bore sections 150, 160 may berepresented by the diameters of the first conduit 10 and of the secondconduit 11, respectively, these being measured perpendicular to thevertical direction V of the heat exchanger 100. More generally, the boresections 150, 160 are to be understood as meaning the surface-areas of aprojection of the first conduit 10 and of the second conduit 11respectively on to a plane perpendicular to the vertical direction V ofthe heat exchanger 100.

It will be appreciated from the foregoing that the first bore section150 is defined by at least one of the first openings 63 a, . . . , 63 i,63 j, . . . , 63 n of the first conduit 10 and that the second boresection 160 as defined by at least one of the second openings 64 a, . .. , 64 i, 64 j, . . . , 64 n formed in the plate 6 a, . . . , 6 i, 6 j,. . . , 6 n.

It then follows from the foregoing that, in the thermal system 500according to the invention, as illustrated in FIG. 1 , the flowrate ofheat-transport liquid circulating in the second conduit 11 is lower thanthe flowrate of heat-transport liquid circulating in the first conduit10. The above-defined second bore section 160, which is smaller than thefirst bore section 150, therefore forms a differentiating member 155differentiating the flowrate of heat-transport liquid within the heatexchanger 100.

Stated differently, the flowrate differentiating member 155 thatdifferentiates the flowrate of the heat-transport liquid is formed hereby at least one of the second openings 64 a, . . . , 64 i, 64 j, . . . ,64 n contributing to defining the second conduit 11 of the first inletheader 1, which has the second bore section 160 smaller than the firstbore section 150 of the first conduit 10 of the first inlet header 1.

It will be appreciated from the foregoing that the differentiatingmember 155 is formed by one of the second openings 64 a, . . . , 64 i,64 j, . . . , 64 n of the second conduit 11. Alternatively, thedifferentiating member may be defined by all of the second openings 64a, . . . , 64 i, 64 j, . . . , 64 n of the second conduit 11.

Because of the presence of this differentiating member 155, theresidence time that the heat-transport liquid spends in the second groupof chambers 76, which is supplied with heat-transport liquid by thesecond conduit 11, is longer than the residence time that theheat-transport liquid spends in the first group of chambers 75 which issupplied with heat-transport liquid by the first conduit 10. Theduration of the exchange of heat between the heat-transport liquidcirculating in the second group of chambers 76 and the refrigerant fluidis therefore longer than the duration of the exchange of heat betweenthe heat-transport liquid circulating in the first group of chambers 75and the refrigerant fluid. This then results in greater effectiveness ofthe exchange of heat that takes place between the heat-transport liquidcirculating in the second group of chambers 76 and the refrigerant fluidcirculating in the pass, as defined hereinabove, that is in contact withthe second group of chambers 76 in the heat exchanger 100.

FIG. 3 schematically illustrates, in section on the vertical andtransverse plane A visible in FIG. 1 , a second example of how a heatexchanger 100 according to the invention may be embodied.

This figure again shows the heat exchanger 100, the first inlet header 1and the first conduit 10 and second conduit 11 of the first inlet header1. This FIG. 3 also again shows two plates 6 i, 6 j of the heatexchanger 100 and a chamber 7 i of the first circuit 110 of theexchanger 100, which chamber is delimited by the aforesaid plates 6 i, 6j. As in the example illustrated in FIG. 2 , the second bore section 160of the second conduit 11 is smaller than the first bore section 150 ofthe first conduit 10. Likewise, in the same way as in the exampleillustrated by FIG. 2 , the heat exchanger 100 comprises the supply unit5, which comprises the first duct 50 fluidically connected to the firstconduit 10 of the first inlet header 1, and the second duct 51fluidically connected to the second conduit 11 of the first inlet header1.

In the variant illustrated by FIG. 3 , at least one of the firstopenings 63 i′, 63 j′ that contribute to defining, in the plates 6 a, .. . , 6 i, 6 j, . . . , 6 n, the first conduit 10, has a third boresection 170 smaller than the first bore section 150 of the first conduit10.

In other words, in this variant, the first conduit 10 of the first inletheader 1 comprises a first portion 10 a of which a bore section issubstantially equal to the aforementioned first bore section 150, and asecond portion 10 b of which a bore section is smaller than theaforesaid first bore section 150 and substantially equal, to within themanufacturing tolerances, to the aforementioned third bore section 170.According to the invention, a ratio between the bore section 170 and thefirst bore section 150 is comprised between 0.4 and 0.8.

According to various embodiments of the invention, just one or severalof the plates 6 a, . . . , 6 i, 6 j, . . . , 6 n that form the secondportion 10 b of the first conduit 10 has a first opening 63 i′, 63 j′ ofwhich the bore section is substantially equal to the aforementionedthird bore section 170. In other words, according to various embodimentsof the invention, just one of the first openings 63 i′, 63 j′ arrangedin the plates 6 a, . . . , 6 i, 6 j, . . . , 6 n that form the secondportion 10 b of the first conduit 10 has a bore section equal to thethird bore section 170, or several, or even all, of the first openings63 i′, 63 j′ arranged in the plates 6 a, . . . , 6 i, 6 j, . . . , 6 nthat form the second portion 10 b of the first conduit 10 have a boresection equal to the third bore section 170.

Advantageously, the chambers 7 i, . . . , 7 n delimited by the plates 6i, . . . , 6 n in which the first opening or openings 63 i′, 63 j′having the third bore section 170 are arranged together form a thirdgroup of chambers 77 of the first circuit 110 of the heat exchanger 100,which group finds itself in contact, in the heat exchanger 100, with athird pass of the second circuit 120 of this heat exchanger. It willthen be appreciated that the first circuit 110 comprises the third groupof chambers 77 which is fluidically connected to the first conduit 10 ofthe first inlet header 1, successively with the first group of chambers75, and that the third bore section 170 of the first conduit 10, whichbore section is located between the first group of chambers 75 and thethird group of chambers 77, forms part of the above-defineddifferentiating member 155.

It then follows from the foregoing that, within the thermal system, theflowrate of heat-transport liquid circulating in the second group ofchambers 76, and the flowrate of heat-transport liquid circulating inthe third group of chambers 77, are reduced in comparison with theflowrate of heat-transport liquid circulating in the first group ofchambers 75.

In one example, the invention may make provision, on the one hand, forthe first group of chambers 75 of the first circuit 110 of the heatexchanger 100 to be in contact with a first pass of the second circuit120, in which pass the refrigerant fluid circulates in essentiallygaseous form and, on the other hand, for the second group of chambers 76of the first circuit 110 of the heat exchanger 100 to be in contact witha second pass of the second circuit 120, in which pass the refrigerantfluid passes in the liquid state, and for the third group of chambers 77of the first circuit 110 of the heat exchanger 100 to be in contact witha third pass of the second circuit 120, in which pass the refrigerantfluid circulates in liquid form and is supercooled by the heat-transportliquid, the temperature of the refrigerant fluid in the liquid statebeing lowered below its saturation temperature.

FIG. 4 schematically illustrates, in section on the vertical andtransverse plane A visible in FIG. 1 , a third example of how theinvention may be embodied. This figure more specifically illustrates theabove-defined supply unit 5 of the heat exchanger 100 according to theinvention, as well as the above-described first duct 50 and second duct51 of this supply unit 5.

According to the example more particularly illustrated by FIG. 4 , theinvention makes provision for the above-defined differentiating member155 to be formed on the first duct 50 fluidically connected to the firstconduit 10 of the first inlet header 1, and by the second duct 51 of thesupply unit 5 fluidically connected to the second conduit 11 of thefirst inlet header 1.

More specifically, according to this example, the invention makesprovision for the first duct 50 of the supply unit 5 to have a firstbore section 500, and for the second duct 51 to have a second boresection 510, the first bore section 500 of the first duct 50 beinggreater than the second bore section 500 of the second duct 51. A ratiobetween the second bore section 500 of the second duct 51 and the firstbore section 500 of the first duct 50 is comprised between 0.4 and 0.8.

It will be appreciated here that the differentiating member 155 isformed by the second bore section 160 of the second duct 51 beingsmaller than the first bore section 500 of the first duct 50. Thedifferentiating member is therefore indeed here supported by the supplyunit 5 rather than, as in the preceding examples, being arrangedactually within the openings 62 a, . . . , 62 i, 62 j, . . . 62 n of theplates 6 a, . . . , 6 i, 6 j, . . . 6 n.

Such an arrangement offers an advantage in terms of cost, in so far asthe advantages of the invention can be combined with a standardizationof all of the plates 6 a, . . . , 6 i, 6 j, . . . 6 n that form the heatexchanger 100. Specifically, there is then no longer any need todifferentiate the manufacture of the various sets of plates havingdifferent openings delimiting the different conduits of the first inletheader 1, since the differentiating of flowrate between the aforesaidconduits is performed upstream of the heat exchange zone, as theheat-transport liquid enters the inlet header 1 made up of theabove-described conduits 10, 11. Such an arrangement furthermore reducesthe risks of errors of assembly during the stacking of the various setsof plates 6 a, . . . , 6 i, 6 j, . . . 6 n having openings 63 a, . . . ,63 i, 63 j, . . . , 63 n, 64 a, . . . , 64 i, 64 j, . . . , 64 n ofwhich the geometric characteristics differ according to whether they areintended to delimit the aforementioned first conduit 10 or theaforementioned second conduit 11 of the first circuit 110.

Whatever the variant considered, the invention makes it possible, usingsimple means, to differentiate the flowrate of heat-transport liquidbetween various regions of the first circuit 110 of the heat exchanger100, so as to differentiate the duration of the exchange of heatperformed between this heat-transport liquid and the refrigerant fluidcirculating in the second circuit 120 of the heat exchanger 100 and thusincrease the efficiency of this exchange in predefined regions of theheat exchanger 100.

It should be noted that this differentiation of the flowrate of theheat-transport liquid within the heat exchanger 100 of a thermal system500 like the one illustrated in FIG. 1 is the result solely of thegeometry of the plates 6 a, . . . , 6 i, 6 j, . . . , 6 n which make upthe heat exchanger 100 and, notably, of the dimensions of the openingswhich, pierced in these plates, delimit therein the first inlet header 1via which the heat-transport liquid is admitted to the first circuit 110of the heat exchanger 100.

According to one method of manufacture in which the plates 6 a, . . . ,6 i, 6 j, . . . , 6 n are, for example, produced by pressing a thinsheet, implementation of the invention therefore proves to be extremelysimple and very low in cost insofar as it requires nothing more than achange to the dimensions of one or more of the openings made in theseplates in order to delimit the first inlet header 1.

The invention as has just been described nevertheless is not limited tothe exclusively described and illustrated means and configurations, andis also applicable to all equivalent means or configurations and to anycombination of such means or configurations.

1. A heat exchanger for a motor vehicle comprising: a first circuitthrough which a heat-transport liquid is intended to pass and whichcomprises a first inlet header via which the heat-transport liquid isadmitted to the first circuit and a first outlet header via which theheat-transport liquid leaves the first circuit, the first circuitcomprising a plurality of chambers which are fluidically connected tothe first inlet header and to the first outlet header and are split intoat least a first group of chambers and a second group of chambers; and asecond circuit through which a refrigerant fluid is configured to passand which comprises a second inlet header via which the refrigerantfluid is admitted into the heat exchanger and a second outlet header viawhich the refrigerant fluid leaves the heat exchanger, the secondcircuit comprising at least two successive passes, the heat exchangerbeing configured to perform an exchange of heat between theheat-transport liquid circulating in at least one of the groups ofchambers and at least one of the passes of the second circuit, whereinthe heat exchanger comprises at least one differentiation member fordifferentiating the per-chamber flowrate of heat-transport liquidcirculating in the first group of chambers from the per-chamber flowrateof heat-transport liquid circulating in the second group of chambers ofthe first circuit.
 2. The heat exchanger as claimed in claim 1, whereineach chamber is delimited by at least two plates, each plate comprisinga bottom wall surrounded by a turned-up edge, the bottom wall beingprovided with at least one opening which at least in part delimits thefirst inlet header, the two plates being positioned one inside theother.
 3. The heat exchanger as claimed in claim 1, wherein the firstinlet header comprises a first conduit supplying the first group ofchambers and a second conduit supplying the second group of chambers,the differentiation member involving a second bore section of the secondconduit that is smaller than a first bore section of the first conduit.4. The heat exchanger as claimed in claim 3, wherein a ratio between thesecond bore section of the second conduit and the first bore section ofthe first conduit is comprised between 0.4 and 0.8.
 5. The heatexchanger as claimed in claim 2, wherein the bottom walls of the atleast two plates each comprise at least a first opening and a secondopening, which respectively make up the first conduit and the secondconduit of the first inlet header.
 6. The heat exchanger as claimed inclaim 4, wherein the differentiation member is formed of at least asecond opening that makes up the second conduit.
 7. The heat exchangeras claimed in claim 5, wherein the differentiation member comprises allof the second openings of the second conduit.
 7. The heat exchanger asclaimed in claim 1, comprising at least one heat-transport-liquid supplyunit, the supply unit being fluidically connected to the first inletheader which comprises a first conduit supplying the first group ofchambers and a second conduit supplying the second group of chambers. 8.The heat exchanger as claimed in claim 7, wherein the supply unitcomprises a first duct supplying the first conduit and a second ductsupplying the second conduit of the first inlet header, thedifferentiation member involving a second bore section of the secondduct that is smaller than a first bore section of the first duct.
 9. Theheat exchanger as claimed in claim 3, wherein the first heat-transportliquid circuit comprises a third group of chambers which are fluidicallyconnected to the first conduit of the first inlet header and to thefirst outlet header successively to the first group of chambers, theheat-transport liquid flowrate differentiation member comprising atleast a third bore section of the first conduit, positioned between thefirst group of chambers and the third group of chambers, the third boresection being smaller than the first bore section of the first conduit.10. A thermal conditioning system for a motor vehicle comprising atleast one heat exchanger as claimed in claim 1.